Circuit breaker



Feb. 16, 1954 J. B. MacNElLL ETAL 2,669,623

CIRCUIT BREAKER Filed Jan. 28, 1950 4 Sheets-Sheet l WITNESSES: INVENTORS John B. MocNeil|,Frifz E. Florschu'rz, Ture Linds'lrom 8 Bernard G. Tremblay. BY v W 4 A ORNEY Feb. 16, 1954 CIRCUIT BREAKER Filed Jan. 28, 1950 4 Sheets-Sheet 2 Fig.2.

WITNESSES: 24

' INVENTORS A John B. MucNeill ,Frirz E. Florschufz,

W ML,

Ture Lindstrom 8| Bernard G. Trembloy.

J. B.- M NElLL ETAL 2,669,623

Time in Seconds Feb. 16, 1954 Filed Jan. 28, 1950 ,343 ,445 OVEROURRENT TRIP RATING MP5. 5. PICKUP A $.DELAY I ms: W f 34' u L z z.

4 Sheets-Sheet 4 Fig.7.

Lon .Tlme

Io: Demgy Pickup Long Tlme Delay Ad ustment 6- Adjustment 2 Short Time Pick-up Adjustment 60 I4 Short Time Delay 1 g Ad'ustment .l I 6 .5 V Instantaneous Time 3 D Instantaneous Pick-up 2 .02 Adjustment A n v l l 4 40 I00 400 I000 4000 wow 40000 Percent Of COII ROhng 4 g Fig John B. MacNeill,Fritz E.F|orschutz,

Ture Lindstromaa Bernara Trembla R I y ATTOR device and a time Patented Feb. 16, 1954 John B. MacNeill, 'schutz, Forest Wilkinsburg, Hills, Ture Lindstrom, Edge- Fritz E. Flor- 'wood, and Bernard G. 'Iremblay, Pittsburgh,

Pennsylvania Westinghouse ration, East Pittsburgh, Pa.,

Electric Corpoa corporation of Application January 28, 1950, Serial No. 141,136 "22 Claims. (01. 200--108) This invention relates to circuit breakersand more particularly to circuit breakers of the t pe used for cont-rolling light to moderate power distribution circuits.

object of the invention is to provide 'a circuit breaker embodying a novel trip device that is operable to trip the breaker after a relatively long time delay in response to overload currents of relative low value, after a relatively short time delay in response to overload currents of intermediate value below a predeteiumined value and instantaneously in response to overload currents above said predetermined value as short -circuinas.

Another object of the invention is to provide a circuit breaker embodying an electromagnetic trip device having a novel time delay device and means for limiting the force applied by the electro'm'agnet to the time delay device.

Another object of the invention is to provide a circuit breaker having a trip device embodying a novel time delay device of the hind dashpot type in which time delays of dilierent duration in different ranges or overload currents are provided by admitting fluid to the dashpot at different rates.

Another object of the invention is to provide a circuit breaker embodying a novel time delay device of the fluid dashpot type wherein different amounts of time delay are provided by the operation of one or more valves to admit fluid to the dashpot at different rates.

Another object of the invention is to provide a circuit breaker embodying a novel trip device and a time delay device of the fluid dashpot type wherein time delays of different durations are provided by the operation of one or more valves for admitting fluid to said dashpot, at least one of the valves being operated electromagnetically in response to overload currents of a predetermined magnitude.

Another object of the invention is to provide a circuit breaker embodying a novel trip device and a time delay device of the fluid dashpot type having separate valve means for controlling the admission of fluid to said dashpot to provide time delay actions of diirerent durations and having adjusting means for adjusting the amount of opening of the valve means to vary the amount of time delay provided by each valve.

A further object of the invention is to provide circuit breaker embodying novel trip delay device of the fluid clashpc't type having a plurality of valves for controlling the admission of fluid to dashpot, certain of said valves being operated electromagnetically, adjusting I the amount of opening of certain of said valves and other adjusting means for selecting the'ini'nimum overload current required to operate certain of said valves. v

Another object of the invention is to prov de a circuit breaker embodying a novel tri device having a time delay device providing time delay tripping of different duration for different ranges of overload currents as tvell as instantaneous tripping, separate adjusting means for varying the amount of time delay in each range and separate adjusting means for selectively determining the minimum overload current requirement for each range of time delay tripping and instantaneous tripping, all '01 the adjusting means be ing disposed for easy access.

The novel features that are considered characteristic of the invention are set "forth in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, vvill be best understood from the following detailed description of a preferred embodiment thereof, when read in connection With the accompanying drawings.

In said drawings:

Fig. 1 is an 'elevational view partly in section of a circuit breaker embodying the principles of the invention; i

Fig. 2 is a vertical sectional view through the trip device taken substantally along line II-II of Fig. 3 and looking in the direction of the arrows;

Fig. 3 is a sectional plan view or the time delay device taken substantially along line III-HI of Fig. 2 and looking in the direction of the arrows;

Fig. 4 is a fragmentary sectional view taken on line IV-IV of Fig. 3 and showing the shorttime delay valve device and the adjusting means therefor;

Fig. 5 is a fragmentary sectional view taken substantially on line V-V of Fig. 3 and showing the instantaneous valve device and the adjusting means therefor;

Fig. 6 is an elevational device showing the scale adjusting knobs;

Fig. 7 is a schematic View of the trip device illustrating the several adjusting means for the time delay device; and

Fig. 3 is a schematic diagram showing the range of adjustment of the trip device.

Referring to Fig. 1 of the drawings, the circuit breaker includes a plurality of pole units each means ror adjusting View of the time delay plate and the several comprising a contact structure indicated gener ally at El, and an overcurrent trip device indicated generally at 53. The contact structure and the trip device for each pole unit are mounted on a separate insulating base I5 which is rigidly secured to a metal panel Il. Since the pole units are alike, only the center pole unit is illustrated and described.

The insulating base I5 for the center pole unit is secured to the panel H by means of screws I9 threadedly engaging metal inserts 2| molded integral with the insulating base I5.

The contact structure I I comprises a stationary main contact 23 and a stationary arcing contact 25, both of which are secured on the inner end of a terminal conducting bar 21 which extends through a suitable opening in the base I5. The stationary arcing contact 25 is rigidly mounted on an upwardly extending portion 29 of the terminal bar 27 which is secured to the base I5 by means of a bolt 3!.

Cooperating with the stationary main and arcing contacts 23 and 25, respectively, is a movable main contact 33 and a movable arcing contact 35.

The movable contact 33 is securedin a suitable manner as by welding to a pivoted contact carrying member 37 and the movable arcing contact is secured by means of screws 39 to the contact member 31.

The contact carrying member 31 is pivotally mounted by means of a pivot pin ti on the upper or free end of a generally U-shaped switch arm 49 having its two legs pivoted by means of separate pivot pins supported in spaced brackets All which are mounted on the base Is by screws e9, there being a separate bracket 51 and pivot pins -35 for each leg of the switch arm 53, only oneof each, however, being shown.

The movable contact carrying member 3'? is electrically connected by means of a flexible shunt 1 conductor 5! to the energizing coil of the trip device lS which will be described later. The upper end of the flexible conductor 5i is rigidly clamped to the lower end of the contact member 31 by means of a plate 53 which has an integral portion 55 of the contact member projecting through an opening therein and having its end riveted over against the plate in the manner shown in Fig. 1. A spring 51 compressed between the plate 53 and a spring seat 59 in the insulating base is provides contact pressure in the closed position of the breaker and also biases the movable contact structure in opening direction.

The movable contact structure is normally maintained in the closed position by an operating mechanism indicated generally at El (Fig. 1) mounted in a U-shaped frame 83. The frame 63 comprises side members 65 (only one being shown) and a cross member 61 and is supported on a platform 69 forming the cross member of a generally U-shaped main bracket comprising a pair of spaced side members H (only one being shown) joined at their outer ends by the cross member or platform $9. The platform 69 extends across the width of the breaker and the side members II are suitably secured to the metal panel I! on the outside of the two outer poles of the breaker.

'The operating mechanism includes a lever 13 pivotally mounted on a pivot pin supported in the side members 95 of the frame 63. The lever 13 comprises a pair of spaced levers joined by a cross member TI and between them supporting a rod 19 which extends across all three poles of the breaker. The rod '59 is operatively connected by means of an insulating connecting member BI to the pivot pin AI in the free end of the switch member 43 on which the movable contact member 3? is mounted. It will be understood that there is provided a connecting member 8i for each pole of the breaker connecting the rod I9 to the movable contact structure for each pole unit so that upon operation of the rod I9 the movable contacts for all three poles move in unison.

An operating linkage comprising toggle links 83, B5 and 8'! is provided to hold the lever I3 and consequently the movable contacts in the closed position and to operate the movable contacts to open and closed positions. The toggle link 93 comprises a pair of spaced links joined by a cross member and is pivotally connected to the lever I3 by a pivot pin 89. Similarly the toggle link comprises a pair of spaced links and is connected by means of a knee pivot pin ill to the toggle link 83 and by a pivot pin 93 to the toggle link 81. The toggle link 87 comprises a pair of links joined by a cam shaped cross member 99 and is pivotally mounted on a fixed pivot 9! supported in the frame 63.

The linkage 83, 85 and 81 comprises two toggles, one of which 83-85 may be designated as the tripping toggle and the other 85-9! as the closing toggle. The tripping toggle 83-85 is normally slightly underset above a line drawn through the pivot pins 89-93 and the closing toggle 85-81 is normally under set below a line drawn through the pivots 91-91.

The tripping toggle 33-85 is normally biased in a direction to cause its collapse by a component of the springs 5'1 which bias the movable contact structures for the three poles of the breaker in opening direction and bias the connecting member 8| toward the left (Fig. 1). The tripping toggle 83-85 is normally prevented from collapsing by means of a main latch member 99 pivoted on the pivot pin 15 and connected by means of a link IIJI to the knee pin 9| of the tripping toggle, the link I9I being connected to the latch member 99 by a pivot pin I03.

The main latch 99 is held in latching position by an intermediate latch lever Iiic pivoted on a pin I91 supported in the frame 93. The latch lever I95 comprises a pair of spaced levers (only one being shown) which between them support a pin I99 upon which is rotatably mounted a latch roller Ill. The lower ends of the latch levers are joined by an arcuate cross member 5 I3 which forms a latch element engaging a light load latch II5 to hold the latch roller H l in engagement with the main latch re. The latch H5 is rigidly mounted on a channel-shaped member II'I pivotally mounted on a pin He supported in the frame 93. The latch lever E95 and the member II: are biased to their latching positions by a spring I2: tensioned between the parts as shown in Fig. l. Ri idly mounted on the right hand end of the channel-shaped member H; is a trip bar I23 which extends across all the poles of the breaker and has secured thereto an insulating bracket I25 for each of the three poles of the breaker. Each of the brackets I25 has a headed screw I2? adjustably mounted therein for cooperation with the trip device as in a manner to be presently described.

It will be seen that as long as the main latch 99 is held in latching position by the latching mechanism just described, the tripping toggle 83-85 will, through the link I9I, be held in the position shown, in which the breaker contacts are heldin the closed position. The closing toggle 85 8'i is biased in a direction to cause its collapse by a spring I29 pin 91, the spring having one end bearing against the cross member 67 and the other end bearing against the knee pivot pin 93 of the closing toggle. The closing toggle 85-81 is normally prevented from collapsing by a shouldered support member I3I pivoted on the pin I61 and biased by means of a spring I33 into supporting an gagement with the knee pin 93 of the closing toggle.

Rigidly secured to the front plate or cross member 61 of the frame 63 is a bearing I 35 in which is rotatably mounted a handle shaft I31. The outer end of the handle shaft I31 carries an operating handle (not shown) and a plate member I39 is secured to the inner end of the shaft I31. The plate member I39 has an outwardly formed portion MI which. in the normal position of the handle, registers with a lug I43 formed inwardly from the cross member 81. A spring I45 coiled about the bearing 535 has its ends bearing against the portion MI and the lug I43 in a manner to bias the shaft I31 and the operating handle in both directions to a central position. The plate I39 is provided with shouldered portions, one of which is shown at $41. which engage the lug I53 to limit the rotary motion of the handle. Also secured to the plate I 39 is a cam member I49 which has the dual function of engaging the free end of the channel-shaped member I I1 to manually trip the breaker open upon movement of the handle in one direction and of engaging the cam on the closing tog" gle 85-81 to manually close the breaker upon movement of the handle in the opposite direction.

Assuming the circuit breaker to be in the closed position as shown in Fig. 1, the breaker is tripped open manually by rotating the handle shaft I31 in the proper direction during which movement the cam member I 49 engages and. actuates the channel-shaped latch member H1 in unlatching direction. This effects release of the latch member H5 whereupon the force exerted by the springs 51 biasing the switch arm 43 in opening direction, transmitted through the connections BI and the lever 13, causes the tripping toggle 83-85 to collapse upwardly and effects opening movement of the movable contact structures of all of the poles of the breaker. When the tripping toggle collapses the link i rotates the latch 99 clockwise, forcing the latch roller Hi to unlatching position where it is held by the arcuate surface on the latch 99.

During the opening movement of the switch arm 43 the springs 51 maintain the arcing concoiled about the pivot tacts in engagement until a tail I5! on the contact member 31 engages the cross member of the switch arm 43. The opening movement of the switch arm 43 is limited by its engagement with extensions on the brackets 41. The opening movement of the lever 13 is arrested by engagement of surfaces I55 on the two legs thereof with ears I51 struck out from the side members of the frame 63. p

The closing toggle 85-81 does not immediately collapse following the release of the latch 99 since it is held by the support I34. However, during the collapsing movement of the tripping toggle the toggle link 85 rotates counterclockwise about the pivot pin 93. During this rotation of the link 85, an ear I53 formed thereon adjacent the pin 93 engages the support member I3I and disengages the shoulder thereon from the pin 93 whereupon the toggle 35-81 collapses downwardly under the bias of the spring I29. The collapse of the toggle 85-81 is assisted by ing a suitable switch (not shown).

the weight of the moving armature of a closing solenoid, which will be discussed later. Collapse of the closing toggle -81 causes resetting of the tripping toggle to thrust transmitting position and resetting of the main latch 99 to latching position. As soon as the latch is reset the spring IZ'I reengages the latch roller I II with the main latch 99 and also reengages the latch member II5 with the latch element II3 to hold the latch roller III in latching position. The mechanism is now in condition for a closing operation.

The contacts are closed either manually. by operation of the shaft I31 by the handle or by a closing solenoid indicated generally at I59. In order to close the contacts manually, the shaft I31 is rotated in the direction of the arrow, that is, clockwise as viewed from the front of the breaker. This operation of shaft I31 engages the eccentric cam I49 with the cam 95 on the toggle link 81, and straightens the toggle tfi-iii. Since, at this time, the knee of the toggle 83-85 is restrained by the link IBI and the main latch 99, the thrust of straightening the toggle 85-81 is transmitted by the toggle link 83 to rotate the lever 13 in a clockwise direction. This movement of the lever 13 is transmitted by the tie rod 12 and the several connectors 81 to the switch arms 43 to simultaneously close the contacts for all of the poles'of the breaker. As the knee pin 93 for the toggle 85-81 arrives at the position shown in Fig. 1, the support I3! is moved by its spring I33 into supporting engagement with the pin 93 to maintain the contacts closed. Upon release of the handle the spring I45 restores the shaft I31 and the cam I49 to their normal position.

The circuit breaker may be closed by energi'zation of the closing solenoid I59 which may effected either manually or automatically by 010s The solenoid I59 comprises a fixed laminated magnet yoke iSI supported on a bracket I63 secured to the under side of the platform 69. The bracket I63 extends downwardly and has feet I65 struck outwardly therefrom to which the magnet yoke ISI is rigidly secured. Also secured to the bracket I63 by means of rivets I6? is a fixed core member #39. A movable armature "I is attached to the lower end of an operating rod I13 which extends upwardly through clearance openings in the fixed core I69, the platform 69 and the channel-shaped trip member H1 and has its upper end pivotally supported on the knee pivot pin 93 of the closing toggle 85-81. An energizing coil I15 wound on an insulating spool is supported on the fixed magnet yoke I 5|.

In the closed position of the breaker (Fig. l} the armature I1! is held in its raised position. When the breaker is tripped open, the closing toggle 55-51 collapses downwardly, as previously described, under the influence of the spring I29 and the weight of the armature I1 I permitting the armature to assume its lower unattracted position. Thereafter, upon energisation of the coil I15, the armature IN is attracted upwardly straightening the toggle 85-81 and closing the contacts.

The breaker is automatically tripped open by operation of the trip device I3 for any pole of the breaker. The trip device includes a tripping e1ectromagnet indicated generally at I11 (Figs. 1 and 2) and a time delay device indicated generally at I19. The tripping magnet I11 comprises c-shaped magnet yoke I81 (Figs. 1 and 2) rigidly secured to the base I5 or its corresponding pole by means of bolts I83 and I85, a fixed core member I81 (Fig. 2), an energizing winding I89 and a movable armature I9I. The bolt I83 which secures the upper end of the magnet yoke 8| to the base also serves to secure the lower end of the flexible conductor I to the upper turn of the winding I89. The lower turn of the winding has a conducting lug I93 electrically and mechanically secured thereto and this lug is secured to a conducting terminal I95 and to the base i5 by means of a bolt I91. The energizing winding I89 is thus electrically connected in series relation in the circuit through the breaker which extends from the terminal 21, the main and arcing contacts 23-39 and -35, the contact member 31, flexible conductor 5 I, energizing coil I89 of the trip magnet to the terminal I95. Upon energization of the tripping magnet the movable armature i9I is attracted upwardly and actuates a trip rod I99 which engages the headed screw I21 to operate the trip bar I23 and trip the breaker.

The movable armature I9I comprises an upper cup-shaped member 2IJI and a lower tubular member 203 rigidly secured together by suitable means such as brazing. The member 29! has a central opening therein and is adapted to. slide over a sleeve 205 surrounding the trip rod. The sleeve 205 is limited in its upward movement relative to the trip rod I99 by means of a spring clip 201 seated in a groove in the trip rod. A spring 299 coiled about the trip rod 599 is compressed between the lower end of the sleeve 295 and the bottom of a counterbore 2I I in the lower element 293 of the movable armature.

The trip rod I99 is moved upwardly to trip the breaker under the control of the time relay device I19 which comprises, generally, a flexible diaphragm 2I3 (Fig. 2) attached to the lower end of the trip rod and several valve elements for admitting air to the space below the diaphragm at various rates to provide for diiierent amounts of time delay. The flexible diaphragm '2I3 is disposed in a chamber 2I5 formed in an upper housing member 2 I 1 and a lower housing member 2I9, both of said housing members being of molded insulating material. The outer edge of the diaphragm 2 I3 is clamped between the housing members 2 I1 and 2 I9, together with a sealing gasket 22I to form an airtight seal. The housing members are secured together and rigidly secured to the magnet yoke I8! by means of bolts 223 (Figs. 2 and 3). The central portion of the diaphragm 2I3 is clamped between upper and lower clamp members 225 and 221, respectively, the upper clamp member 225 having an annular projection 229 extending downwardly through an opening in the lower clamp member 221 and formed over against the lower face of the latter to form an airtight seal.

Secured to the lower end of the trip rod I99 is a sleeve 23I having a flange 233 thereon brazed to the bottom face of the upper clamping member 225. The lower portion 203 of the movable armature extends downwardly through an opening in the upper wall of the chamber 2I5 above the diaphragm and is seated on the upper face of the clamping member 225. The spring 299 biases the trip rod I99 upwardly and biases the movable armature I9I downwardly. This results in biasing the lower end of the armature member 293 downward against the upper face of member 225.

Since the spaces above and below the diaphragm 2 I3 are completely sealed 01'1" from each other and the space abovethe diaphragm is at atmospheric pressure, any force tending to raise the trip rod I99 will be restrained by the partial vacuum below the diaphragm. In order to control the rate of tripping movement of the trip rod I99 several valve devices are provided to admit air to the space below the diaphragm. The valve devices comprise a long-time delay valve indicated generally at 235 at the bottom of Fig. 2, a short time delay valve device indicated generally at 231 in Figs. 3 and 4 and an instantaneous valve device indicated generally at 239 in Figs. 3 and 5.

The long time delay valve device 235 will be described first. The central bottom portion of the housing member 2I9 is molded to form a valve seat 24I in the shape of an inverted truncated cone. Surrounding the valve seat 231 is a tubular metallic member 243 molded into the housing member 2I9 and threaded internally to receive a valve 245 having a conical opening therein for cooperating with the valve seat 24L The valve 235 is provided with a flange 241 for supporting a knurled adjusting knob 249 of molded insulating material which is biased thereagainst by a spring 25I coiled about the tubular member 293 and compressed between the bottom or the housing member 2I9 and upper surface of the adjusting knob 239. The outer portion of the knob is formed to provide a flange 253 extending outwardly and upwardly and cooperating with a flange 255 molded integral with the housing member to support and retain in place a suitable filter material indicated by the reference numeral 251 through which air is admitted to the chamber 2I5 below the diaphragm. It will be noted that an air passage 259 in the form of a groove is provided along the threaded surface of the valve 295 and a passage 25! is provided axially through the valve seat 2M. The flow of air into the chamber below the diaphragm is through the filter 251, the passage 259, the orifice defined by the valve 245 and the valve seat and through the passage 26:.

The inner surface 293 of the knob 299 is provided with serrations which cooperate with corresponding serrations on the valve 235, whereby rotation of the knob 249 also rotates the valve 235 which, due to its threaded engagement with the fixed tubular member, moves the valve axially oir the valve seat 24I to thereby vary the rate of admission of air below the diaphragm and, hence, varies the amount of time delay.

The valve device just described is calibrated by pushing upwardly on the knob 2 39 to disengage it from the valve member 245. The knob 249 is then set to zero and the valve member 235 rotated to the closed position. Thereafter the knob 299 is released and restored to engagement with the valve by the spring 25I. The knob 299, together with the valve 245, is then rotated to the position to provide the required time delay. The knob 249 is limited in rotation to approximately 360 by means of a projection 295 molded integral with the knob engaging a projection 291 molded integral with the housing member 2I9.

The periphery of the knob 249 is provided with serrations as at 269 which are engaged by a spring pressed pawl 21I to retain the knob in its adjusted position.

The short-time delay valve device 231 (Fig. 4) controls a passage for admitting air from the chamber 2I5 above the diaphragm 2I3 to the space below the diaphragm at a rate to provide tripping with a very short time delay in the order of alternating current cycles. The valve device 231 comprises a tubular valve element 213 (Fig. 4) disposed in an opening 215 in thehous- 2&69 628 ing member 211 and having an enlarged head portion 211 seated in an opening 219 in the housing member 219. The valve element 213. is provided with a valve seat and a valve 281 slid-- able in the tubular valve element 213 normally cooperates with the valve seat to close a communication with opposite sides of the diaphragm. The valve element 213 is provided with an axial passage 283 in which is disposed; a tapered projection 285 of the valve 281 and which is normally closed by the valve 281. The head 211 of the valve element 213 is provided with horizontal passages 281 disposed at right angles to each other. A passage 289 in the housing member 2 I 1 communicates the chamber 215 above the diaphragm 213 to the opening 215 above the valve seat and a passage 291 in the housing member 219 communicates the chamber 215below the diaphragm 213 with the passages 28?.

It will be seen that upward or opening movement of the valve 281 will open the passage 283 and establish a communication from the upper side to the lower side of the diaphragm through the passages 289, 283, 281 and 291.

The valve 281 is actuated to open position by means of an armature 293 which is biased to unattracted positionby a spring 294 and is attracted upwardly by the tripping magnet 111 when this magnet is energized by overloads in an intermediate range of overloads of, for instance, 200% to 100()% of normal rated current. The armature 293 is shown in Fig. 3 broken away, but with the outline thereof shown by dot and dash lines. A portion of the armature 293 also appears in Fig. 4 of the drawings. An opening 299 (Fig. 4) in the magnet; yoke 181 provides an air gap for the magnetic circuit through the armature 293. The armature 293 is provided with outwardly extending projections 295 (Fig. 3) which are seated in a recess 291 in the upper portion of the housing member 211 to pivotally support the armature. A bracket 299 (Fig. 4), secured by means of rivets 3111 to the armature 293, has a semi-circular opening 303 (Fig; 3) therein which engages in a notch, 305 in the upper end of the valve 281 so that upon actuation of the armature 293 the bracket 299 engages a substantially semi-circular head 301 on the valve 281 and moves the valve to open position. This opens the previously described communication permitting air to pass from the chamber 215 above the diaphragm to the space below the diaphragm to control the tripping movement of the trip rod 199 (Fig. 2). The rate of flow of air to the space below the diaphragm and consequently the rate of tripping movement of the trip rod are controlled by the amount of opening of the valve 281. a v v The opening movement of the valve 281 is adjustably controlled by means of an adjustable S-shaped stop member 309 (Figs. 3 and 4). The upper portion. 311 of the s-shaped member corn-.- prises an adjustable stop and is disposed in the path of tripping movement of the upturned end of the armature 293 to be engaged thereby and thus limit the upward movement of the armature 293 and limit the extent of opening of the valve 281. The center cross bar 313 of the S- shaped member 309 has a threaded opening therein which is engaged by a reduced threaded portion 315 of an adjusting screw 311, so that upon rotation of the screw 311 the s shaped member 309 will be moved upor down, depending upon the direction of rotation. to provide for greater or lesser movement of the armature 10 29 3 and hence, greater or lesser opening movement of the valve 281.

The lower end of the adjusting screw 311 has a reduced fluted portion molded into an insulating knob 319. The knob 319 is rotatably mounted in a cross bar 321 of molded insulating material. The cross bar 321 is supported on the underside of the housing member 211 by means of screws 323 only one of which is shown. The knob 319 is provided with a hanged portion 325 which is pressed against the bottom face of the cross bar 321 by means of a spring washer 321 seated in annular groove in the adjusting screw. The spring washer 921 is compressed between the upper surface of the cross bar 321 and a C-shaped washer 329 also engaging in the groove in the adjusting screw. A spring 331 disposed in a recess in the cross bar 321 engages a square portion 333 of the knob 319 to retain the knob at each quarter rotation thereof.

The adjusting screw 311 has an enlarged threaded portion 335 which passes through a clearance opening in the bottom portion of the S-shaped member and threadedly engages an indicating member 331. The lower vertical portion of the S-shaped member 369 has cut-away portions on opposite edges thereof which are engaged by projections on the member 331 so that the latter will travel up and down without rotating. At the outer edge the member 331 is provided with a pointer 333 extending through a vertical slot 3&9 (Fig. 6) in an index plate 341 supported at its lower end on the cross bar 321 and having its upper end secured to a cross member 343 molded integral with side members 395, which in turn, are molded integral with the housing member 211.

The thread on the portion 335 of the adjusting screw has approximately twice the lead as the thread on the portion 315, hence, for one rotation of the adjusting screw the member 331 and the pointer 339 will move twice the distance as the S-shaped member 309. This makes possible an expanded dial on the index plate 341 and provides for more accurate setting of the short time delay device.

The valve 281 is rmovably supported in the opening 215 and may readily be removed for inspection by removing a plug 341 which normally closes the opening 219 in which the head 211 of the valve member 213 is disposed. With the plug 341 removed, the valve member 211 is rotated in a direction to bring a key see into alignment with a vertical slot (not shown). means of a pin 351 in the valve 281 cooperating with a cut-away portion 353 in the valve member 213 the valve 281 is caused to rotate with the member 213 to align the semi-circular head 3e? (Fig. 3) thereof withthe opening 383 (Fig. 3) in the bracket 299. The valve 281 and the valve member 213 may then be bodily removed from the housing. The valve is inserted in the housing by the reverse of the above procedure. The key 349 is aligned with the vertical key way (not shown) which also aligns the semiwircular head 301 with the opening 3&3 (Fig. The valve assemblage is then thrust upwardly as far as it will go and given a rotation to en a e the groove 305 with the bracket 229 on the armature 293. The plug 341 is then inserted 11d tightened against the head 21?- to retain the valve structure securely in place.

The instantaneous valve device 23:? shown in Fig. 5 is essentially the same as the short time delay valve device of Fig. 4-, except that the tapered end 295 is omitted. The instantaneous valve device 239 comprises a valve 355 slidable axially in a valve member 35? removably supported in an opening 359 in the housing member 2 IT. The valve member 35'! is provided with a head 36! disposed in an opening 363 in the housing member 2 l 9 and rigidly held in place by a plug 365 which threadedly engages in the opening 363.

The upper end of the valve 355 is provided with a groove 361 forming a semi-circular head 3B9 (Figs. 3 and 5) adapted to cooperate with a bracket 3'II secured by means of rivets 313 to an armature 315. The bracket 31! is provided with a semi-circular spring 3H 369 of the valve 355. The and replacing the valve assembly of the instantaneous valve device is the same as that described for the short time delay valve device.

The armature 3'I5 is similar to the armature 293 and is provided with pivot projections 919 for pivotally supporting the armature 315 in the recess 29'! in the upper face of the housing member 227. The free end of the armature 375 is biased by means oi a spring 38I to its unattracted position. The magnet yoke IN is provided with an opening 392 (Fig. 5) which serves as an air gap for the magnetic circuit through the armature 315.

The valve member 357 is provided with an axially extending passage 383 which is normally closed by thevalve 355. When the valve 355 is moved to its open position it establishes a communication from the chamber 215 above the diaphragm 2I3 to the space below the diaphragm through a passage 385, the passage 353, a horizontal passage 38'! in the head 36I and a passage 389.

The pickup point, that is, the magnitude of overload current required to actuate the armatures 293 and 3'55 may be varied by varying the tension of their respective springs 29d and 381. The upper end of the springs 294 and 38I are attached to their respective armatures and their lower ends are attached to movable members 39! and 393, respectively. The members 39I and 393 threadedly engage adjusting screws 395 and 391 respectively. The lower ends of the screws 395 and 331 are molded into insulating knobs 399 and method of removing 400 (Figs. 6 and 7) rotatably mounted in the cross l member 32L Upon rotation of the screws 395-49? their associated members 39I393 are moved up or down, depending on the direction of rotation to vary the tension or their respective springs, thus varying the pickup points of the armatures 293 and 375. The movable members 39I and 393 are provided with pointers 401 and 403, respec tively which extend through vertical slots 102 and 404 (Fig. 6) in the scale plate 3M to prevent rotation of the movable member and to indicate the settings of the devices.

The pickup point for the movable armature I9I (Fig. 2) of the tripping electromagnet I11 may be similarly adjusted. The armature I9I is biased against attraction by means of springs $05 (Figs. 2 and 3) which have their upper ends attached to a U-shaped yoke dill which has its two legs pivotally supported in spaced, grooved studs 409 supported in the housing member 2II substantially as shown in Figs. 2 and 3. The right hand end of the yoke 401 is provided with inwardly extending projections ii! which engage in an annular groove 4E3 (Fig. 2) in the lower member 203 of the armature I9I. The

for receiving the head lower ends of the springs 405 are attached to a movable member M5 which threadedly engages an adjusting screw M7. The lower end of the adjusting screw 411 is molded into an insulating knob M9 rotatably mounted in the cross member 32!. The movable member tit is rovided with a pointer 42I extending through a slot 423 (Fig. 2) in the scale plate 3M to prevent the movable members from turning and to indicate the setting. It will be understood that the scale plate 3M bears indicia adjacent the several pointers indicating the settings of the several adjusting devices.

The trip device operates with time delays of difierent durations in two distinct ranges of overcurrents below a predetermined magnitude, and instantaneously in response to overcurrents above the predetermined magnitude, or in response to short circuit currents. The ranges of overcurrents may be arbitrarily defined as, for example, a low range up to 500% or 600% of normal rated current, an intermediate range between 500% or 600% and 1000% of normal rated current, and instantaneous 1000% or more of normal rated current.

Assuming an overcurrent within the low range of overcurrents the trip device, referring particularly to Fig. 7, will operate as follows: Upon the occurrence of an overcurrent in the low range the tripping electromagnet becomes energized and attracts the armature I9i upwardly. The armature acts through the spring 209 and the sleeve 225 to produce an upward thrust on the trip rod 199, the movement of the trip rod being retarded by the partial vacuum below the diaphragm 2I3. The trip rod I99 moves slowly in tripping direction as air is drawn into the space below the diaphragm through the long time delay valve 235 until the upper end of the trip rod engages the headed screw l2? (Fig. 1) and actuates the latch mechanism to efiect tripping the breaker in the manner previously described. The time delay provided by the long time delay device 235 is in the order of seconds and may be varied by adjusting the valve 241445 as set forth previously.

As soon as the breaker contacts are opened the tripping magnet ITI is deenergized and the armature HM and the trip rod I99 are restored by means of the springs 405 and the force of gravity to their Fig. 2 positions. A spring biased bypass valve 425 (Fig. 2) controls a passage through the diaphragm 2I3 to provide for quick restoration of the armature I9I, the trip rod I99 and diaphragm 2I3 to their normal positions following a tripping operation.

When an overcurrent occurs in the intermediate range of overcurrents, the electromagnet ITI is energized sufficiently to attract the short time delay armature 293 (Figs. 4 and 7) upwardly against the adjustable stop 9 opening the short time delay valve 28I an amount determined by the adjustment of the stop 3| I. This admits air to the space below the diaphragm 2I3 at a higher rate than the long time delay valve alone and provides a relatively short time delay in the order of cycles in the tripping operation.

Energization of the tripping magnet IT! in response to an overcurrent in the intermediate range is not sufiicient to attract the armature 315 for the instantaneous valve 239 (Fig. 5). However, upon the occurrence of an overcurrent of 1000% or more of rated current both the short time delay armature 293 and the instantaneous armature 315 are actuated and open both device varies with the 13 the short time delay valve 28 (Figs. 4 and 7) and the instantaneous valve 355 (Figs. 5 and 7), thereby admitting air to the space below the diaphragm 2 I 3 at a rate suflicient to permit substantially instantaneous tripping movement of the trip rod I}.

On short time delay and instantaneous tripping operations the spring 209 limits the force applied by the moving armature [9! to the time delay device. On such operations the armature [BI is attracted immediately against the fixed core member I81 compressing the spring 239 which then supplies the force necessary to actuate the trip rod. Thus the pull exerted on the time delay device is limited to the maximum force exerted by the spring 209 when it is compressed. This prevents damage to the time delay device and also provides a uniform pull on the time delay device.

The herein disclosed circuit breaker is well adapted for the protection of distribution systems. Such distribution systems are usually protect-ed by a series of breakers including generator breakers, bus tie-in breakers, feeder breakers and load breakers. The circuit breakers of such a system are usually set for selective tripping, that is, if a fault should occur at any point in the system, the breaker nearest the-fault and on the generator side of the fault should open to clear the fault condition.

The time-current requirement of the tripping position of the breaker in the selective system for which reason a trip device providing a wide range of adjustment is essential.

As shown in Figure 8, the trip device is capable of a wide range of adjustments. There are five separate adjusting devices all located for ease of accessibility. By way of example of the ranges of adjustment, the following have been arbitrarily selected for illustrative purpose:

1. Range of long time delay pickup, from 80 to 160% of coil rating.

2.. Range of long time delay, from 23 to 86 seconds.

3. Range of short time delay pickup, from 500 to 1000% of coil rating.

4. Range of short time delay, from 4. to 30 cycles.

5. Range of instantaneous pickup from 1000 to 1500 per cent of coil rating.

Figure 8 graphically illustrates the ranges of the several adjustments of the trip device. Along the left hand edge of Fig. 8 is indicated the time in seconds. At the bottom is indicated the percent of coil rating and along the right hand edge is shown the time in cycles based on 60 cycle frequency. The curve A represents the minimum settings of the adjustments and the maximum settings are represented by thecurve B. By 'adjusting the knob H9 (Figs. 2, 6 and 7) the long time delay pickup may be adjusted to pick up at any point .in the band of adjustments defined by curves .A and B as indicated at C, that is, by way of example, between 80% and 160% of coil rating. Adjusting the knob 249 (Figs. 2, '6 and 7) which controls the longtime delay valve 2-35 varies the amount of long time delay between 23 and 8.6 seconds as indicated at D in Fig.8. As indicated at E (Fig. 8) the short timedelay pickup may 'be i set to pick up between 500%- rating. This is effected by 3.99 (Figs. 6 and 7).

and 1000% of'coil adjusting the knob The amount of short time delaymay be varied between *4 and 530- cycles, as

.indicatedaeF, by adjustm'g the knob- M9 li ies.

4, 6 and 7). Finally the instantaneous pickup point may be varied between 1000 and 1500 of coil rating, as indicated at G, by adjusting the knob 400 (Figs. 5, 6 and 7) which controls the tension of the biasing spring 38f (Figs. 5 and 7) for the instantaneous valve operating armature 315.

Each of these adjustments. may be made by merely turning the adjusting knob associated with the particular adjusting devices previously described. The adjustments are independent of one another and, as shown in Fig. 6,. all of the adjusting knobs are conveniently located.

The complete adjustability of the trip device eliminates the necessity of increasing band width of adjustments to compensate for manufacturing variations and different coil ratings. The variation of tripping time due to temperature change is negligible. This is made possible by using air as the delaying medium. The tripping time depends on the velocity with which the air flows through the valve orifices and is not aifected by changes in air density.

Having described the invention in accordance with the patent statutes, it is to be understood that various changes and modifications may be made in the structural details and combination of elements disclosed without departing from some of the essential features of the invention.

We claim as our invention:

1. In a circuit breakenan electromagnetic trip device comprising an energizing winding, an armature operable upon energization of said Winding in response to overload currents, a time delay element having achamber, a movablemember connected to said time delay element and movable by said armature, means admitting fluid to said chamber at a predetermined rate to. retard movement of said movable member with a predetermined time delay, valve means operable to increase the rate of admission of fluid to said chamber to thereby decrease the amount of time delay, and separate magnetic means responsive to predetermined overload currents in said winding for operating said valve means.

2. In a circuit breaker, an electromagnetic trip device comprising an energizing winding, an armature operable upon energization of said winding in response to overload currents, a time delay element having a chamber, amovable member attached to said time delay element and movable by said armature, adjustable valve means for admitting fluid to said chamber at a predetermined rate to retard movement of said movable member with a relative long time delay, a second valve means operable to increase the rate of admission of fluid to said chamber to retard movement of said movable member with a relative short time delay, and separate electromagnetic means responsive to overload currents of predetermined value in said winding for operating said second valve means.

3. In a circuit breaker, an electromagnetic trip device operable to effect automatic operation of said breaker, said trip device comprising a mov able member, an energizing winding, an armature operable upon energization of said winding to actuate said movable member, a time delay element for retarding tripping movement of said movable member having a chamber, a first valve means for admitting fluid to said chamber at a predetermined rate to retard tripping movement of said movable member with a relatively long time delay, adjusting means for adjusting said first valve means'to vary the rate er al-mission to actuate of fluid to said chamber to thereby vary the amount of time delay provided by said first valve means, a second valve means operable automatically by said electromagnetic trip device in response to predetermined abnormal circuit conditions to increase the rate of admission of fluid to said chamber to retard tripping movement of said movable member with a relatively short time delay, and separate magnetic means for operating said second valve means.

4. In a circuit breaker, an electromagnetic trip device operable to effect automatic operation of said breaker, said trip device comprising a movable member, an energizing winding, an armature operable upon energization of said winding to actuate said movable member, a time delay element attached to said movable member for retarding trippin movement of said movable member having a chamber, a first valve means for admittin fluid to said chamber at a predetermined rate to retard tripping movement of said movable member with a relatively long time delay, a second valve means operable automatically by said electromagnetic trip device in response to predetermined abnormal circuit conditions to increase the rate of admission of fluid to said chamber to retard tripping movement of said movable member with a relatively short time delay, and a separate armature for actuating said second valve means.

5. In a circuit breaker, an electromagnetic trip device operable to effect automatic opening of said breaker, said trip device comprising a, movable member, an energizing winding, an armature operable upon energization of said winding to actuate said movable member, a time delay element comprising a flexible diaphragm for retarding tripping movement of said movable member, a normally open chamber, a first valve means for admitting fluid to said chamber at a predetermined rate to retard movement of said movable member with a predetermined time delay, a second valve means, and a second armature electromagnetically operated in response to predetermined abnormal circuit conditions for actuating said second valve means to increase the rate of admission of fluid to said chamber.

6. In a circuit breaker, a movable member operable to eiiect automatic operation of said breaker, a trip device comprising electromagnetic means including an armature operable when energized in response to overload currents said movable member, time delay means comprising a normally open fiuid dashpot for retarding tripping movement of said movable member, means defining a normally open restricted passage admittin fluid to said dashpot to retard tripping movement of said movable member with a relatively long time delay when said electromagnetic means is energized in response to an overload current below a predetermined value, means defining a relatively large passage for admitting fluid to said dashpot, a valve operating armature, and a valve paerable by said valve operating armature when said electromagnetic means is energized in response to an overload current above said predetermined value, said valve opening said relatively large passage to permit said electromagnetic means to actuate said trip member substantially instantaneously.

7. In a circuit breaker, a movable member onerable to efiect automatic operation of said breaker, a trip device comprising electromagnetic means including an armature operable said movable member when energized in response to overload currents .to actuate said movable member, time delay means comprising a fluid dashpot connected to for retarding tripping movement of said movable member, means defining a restricted passage admitting fluid to said dashpot to retard tripping movement of said movable member when said electromagnetic means is energized in response to an overload current below a predetermined value, means defining a relatively large passage for admitting fluid to said dashpot, a valve operating armature, and a valve operable by said valve operating armature when said electromagnetic means is energized in response to an overload current above said predetermined value, said valve opening said relatively large passage to permit said electromagnetic means to actuate said movable member substantially instantaneously.

8. In a circuit breaker, a member movable to effect automatic operation of said breaker, electromagnetic means for actuating said movable member, time delay means comprising a fluid dashpot for retarding movement of said movable member, a normally open valve for admitting fluid to said dashpot at a predetermined rate for effecting a long time delay of the order of seconds in th operation of said movable member, a second valve for admitting fluid to said dashpot at a greater rate than said first valve for efiecting a short time delay of the order of cycles in the operation of said movable member, a third valve for admitting fluid to said dashpot at a rate to permit substantially instantaneous operation of said movable member, and separate armatures for actuating said second and third valves.

9. In a circuit breaker, trip means operable to efiect automatic operation of said breaker, electroresponsive means for operating said trip means, time delay means comprising a fluid dashpot connected to said trip means for retarding tripping operation of said trip means, a first valve means for admitting fluid to said dashpot at a predetermined rate for effecting a long time delay of the order of seconds in the operation of said trip means, a second valve means for admitting fluid to said dashpot at a greater rate than said first valve for efiecting a short time delay of the order of cycles in the operation of said trip means, a first armature operable when said electroresponsive means is energized in response to overload currents below a predetermined value for actuating said second valve, a third valve for admitting fluid to said dashpot at a rate to permit instantaneous operation of said trip means, and a second armature operable when said electroresponsive means is energized in response to overload currents above said predetermined value for actuating said third valve.

10. In a circuit breaker, a movable member operable to effect automatic operation of said breaker, electromagnetic trip means, means for operating said movable member, time delay means comprising a fluid dashpot connected to said movable member for at times retarding tripping operations of said movable member, a first valve means for admitting fluid to said dashpot at a predetermined rate for efiecting a time delay in the operation of said movable member, a first armature operable when said electromagnet is energized in response to overload currents below a predetermined value for opening said first valve means, a second valve means for admitting fluid to said dashpot at a rate to permit instantaneous operation of said movable member. and a 17 second ormatureoperable when said electromagnet is energized in response to overload currents above said predetermined value for opening said second valve means,

11. In a circuit breaker, a movable member operable to effect automatic operation of said breaker, electromagnetic trip means, means for operating said movable member, time delay means comprising a fluid dashpot for at times retarding tripping operations of said movable member, a first valve means for admitting fluid to said dashpot at a predetermined rate for effecting a time delay in the operation of said movable member, a first armature operable when said clectromagnet is energized in response to over.- load currents below a predetermined value for opening said first valve means, adjusting means for selectively determining the extent of open! ing of said first valve, 2. second valve means for admitting fluid to said dashpot at a rate to permit instantaneous operation of said movable member and a second armature operable when said electromagnet is energized in response to overload currents above said predetermined value for opening said second valve means.

' 12. In a circuit breaker, a movable member operable to effect automatic operation of said breaker, electromagnetic trip means, means for operating said movable member, time delay means comprising a fluid dashpot connected to said movable member for at times retarding tripping operation of said movable member, a first valve means for admitting fluid to said dashpot at a predetermined rate for effecting a time delay in the operation of said movable member, a first armature operable when said electromagnet is energized in response to overload currents below a predetermined value for opening said first valve means, a second valve means for admitting fluid to said dashpot at a rate to permit instantaneous operation of said movable member, and a second armature operable when said electromagnet is energized in response to overload currents above said predetermined value for opening said second valve means, and separate adjusting means for said first and second armatures for selectively determining the minimum overload current required to actuate said armatures.

13. In a oircuitbreaker, a trip rod operable to efiect automatic operation of said breaker, an energizing winding, a main armature operable upon energization of said winding in response to overload currents to actuate said trip rod, time delay means comprising a fluid dashpot operated by said trip rod for retarding operation of said trip rod, a first valve means for admitting fluid to said dashpot at a predetermined rate for effecting a time delay in the operation of said trip rod when said winding is energized in response to overload currents below a predetermined value, a second valve means for admitting fluid to said dashpot at a rate to permit instantaneous operation of said trip rod, a second armature operable when said winding is energized in response to overload currents above said predetermined value to open said second valve, and resilient means disposed between said main armature and said trip rod to limit the force applied by said armature to said trip rod.

14. In a circuit breaker, a trip rod operable to effect automatic operation of said breaker, an energizing winding, a main armature operable opon energization of said winding in response to overload currents to actuate said trip rod, means adjustable to selectively determine the mini- 18 mum overload current required to actuate said main armature, time delay means comprising a fluid dashpot connected to said trip rod for retarding operation of said trip rod, a first valve means for admitting fiuid to said dashpot at a predetermined rate for effecting a time delay in the operation of said trip rod when said winding is energized in response to overload currents below a predetermined value, a second valve means for admitting fluid to said dashpot at a rate to permit instantaneous operation of said trip rod, a second armature operable when said winding is energized in response to overload currents above said predetermined value to open said second valve, and means adjustable to selectively determine the minimum overload current required to actuate said second armature.

15. In a circuit breaker electroresponsive trip means for effecting automatic operation of said breaker comprising a trip rod, an armature operable to actuate said trip rod, spring means disposed between said armature and said trip rod to limit the force applied by said armature to said trip rod, time delay means for retarding tripping operation of said trip rod comprising a fluid dashpot, normally closed valve means for admitting fluid to said dashpot at a predetermined rate, a valve operating armature operable upon energization of said electroresponsive means in response to an overload current of predetermined value to open said valve, an adjustable stop for limiting the opening movement of said valve operating armature, and adjusting means for varying the setting of said adjustable stop to vary the extent of opening of said valve and the amount of time delay provided thereby.

16. In a circuit breaker, electroresponsive trip means for eflecting automatic operation of said breaker comprising a trip rod, an armature op.- erable to actuate said trip rod, spring means dis.- posed between said armature and said trip rod to limit the force applied by said armature to said trip rod, time delay means for retarding tripping operation of said trip rod comprising a fiuid dashpot, normally closed valve means for admitting fiuid to said dashpot at a predetermined rate, a valve operating armature operable upon energization of said electroresponsive means in response to an overload current of predetermined value to open said valve, biasing means for biasing said valve operating armature against operation, and adjusting means for varying the amount of bias of said biasing means to vary the minimum overload current required to operate said valve operating armature.

17. In a circuit breaker, an electromagnetic trip device for effecting automatic operation of said breaker including a trip rod, a main armature movable to actuate said trip rod, said armature at times being movable relative to said trip rod, resilient means disposed between said armature and said trip rod, time delay means for retarding tripping movement of said trip rod comprising a fluid dashpot connected to said trip rod, a plurality of valve means for admitting fiuid to said dashpot at different rates, a separate valve operating armature for each of said valve means, and separate adjusting means for said in in armature and each of said valve operating armatures for selectively determining the minimum current required to operate each of said armatures.

18. In a circuit breaker, electromagnetic trip means for effecting automatic operation of said breaker including a trip rod, a main armature 19 movable to actuate said trip rod, time delay means for retarding tripping movement of said trip rod comprising a fluid dashpot connected to said trip rod, a plurality of valve means for admitting fluid to said dashpot at different rates in response to overload. currents of different magnitude, separate means for adjusting each of said valve means for varying the rate of admission of fluid to said valve means to thereby vary the amount of time delay provided by each of said valve means, and a separate armature for operating each of said valve means.

19. In a circuit breaker, electromagnetic trip means for efiecting automatic operation of said breaker comprising a trip rod, a main armature movable to actuate said trip rod, time delay means for retarding tripping movement of said trip rod comprising a fluid dashpot, a plurality of valve means for admitting fluid to said dashpot at different rates, a separate valve operating armature for operating each of said valve means in response to overload currents of different magnitude, separate biasing means for said main armature and each of said valve operating armatures, and a separate adjusting device for adjusting each of said biasing means to vary the minimum overload current required to operate said main armature and each of said valve operating armatures.

20. In a circuit breaker, having a movable member operable to effect automatic operation of aid breaker, electromagnetic means for operating said movable member, a single time delay element for retarding operation of said movable member, a first control element for controlling said time delay element to effect a relatively long time delay in the operation of said movable member, adjusting means for adjusting said first control element to vary the amount of time delay provided by said first control element, biasing means for said electromagnetic means, adjusting means for adjusting said biasing means to vary the minimum overload current requred to operate said movable member, a second control element for controlling said time delay element to eiTect a relatively short time delay in the operation of said movable member, adjusting means for adjusting said second control element to vary the amount of time delay provided by said second control element, biasing means biasing said second control element against operation, adjusting means for adjusting said biasing means to vary the minimum overload current required to operate said second control element, a third control element for controlling said time delay element to efiect instantaneous operation of said movable member, means biasing said third control element against operation, and adjusting means for adjusting said bias- 20 mg means to vary the minimum current required to operate said third control element.

21. In a circuit breaker, a movable member operable to efiect automatic operation of said breaker, electroresponsive means for operating said movable member, a single time delay member for retarding tripping operation of said movable member, a first control element for controlling said time delay member to effect a relatively lon time delay in the operation of said movable member, a second control element for controlling said time delay member to effect a relatively short time delay in the operation of said movable member, separate adjusting means for independently adjusting said first and second control elements to vary the amount of time delay provided by each of said control elements, a third control element for controlling said time delay member to efiect instantaneous operation of said movable member and separat electroresponsive means for actuating said second and third control elements.

22. In a circuit breaker, a movable member operable to effect automatic operation of said breaker, electroresponsive means for operating said movable member, biasing means biasing said electroresponsive means against operation, adjusting means for adjusting said biasing means to vary th minimum overload current required to operate said movable member, time delay means for retarding operation of said movable member, a control element for controlling said time delay means to effect a predetermined time delay in the operation of said movable member, electromagnetic means for operating said control element, adjusting means for adjusting said electromagnetic means to vary the minimum overload current required to operate said electromagnetic means, a second control element for controlling said time delay means to efiect instantaneous operation of said movable member, a second electromagnetic means for operating said second control element, and adjusting means for adjusting said second electromagnetic means to vary the minimum overload current required to operate said second electromagnetic means.

JOHN B. MACNEILL. FRITZ E. FLORSCHUTZ. TURE LINDSTROM. BERNARD G. TREMBLAY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,154,359 Basch Sept. 21, 1915 2,295,691 Russell Sept. 15, 1942 2,451,962 Lindstrom et a1. Oct. 19, 1948 2,486,596 Graves Nov. 1, 1949 2,543,410 Jensen Feb. 27, 1951 

